The field of the present invention relates to intravascular stent grafts. In particular, a bifurcated side-access intravascular stent graft and methods for fabricating and deploying the same are described herein.
In many instances of vascular disease, a damaged, weakened, and/or enlarged portion of a blood vessel must be protected from intravascular fluid pressure. Continued exposure to such fluid pressure may result in progression of damage to the affected area and/or vessel failure, accompanied by significant morbidity or even sudden death. A well-established technique for treating such vascular damage is the use of transluminally-deployed stent grafts.
Briefly, a stent graft comprises two major components, a stent and a graft. The stent (one or more) typically takes the form of a somewhat stiff tube-like structure inserted into an affected vessel and fixed in place. The stent may serve to maintain a patent vessel lumen, may serve as structural support for the vessel, and/or may serve as an attachment/seal for a graft. A graft typically takes the form of a flexible tube or sleeve which is at least somewhat fluid-tight (although varying degrees of permeability may be desirable for a variety of reasons). When secured within a vessel using stents (a single stent the length of the graft, a pair of stent segments at the ends of the graft, or multiple stent segments spaced along the length of the graft), the graft becomes a surrogate vessel-within-a-vessel, and bears the brunt of the intravascular fluid pressure. It has become common practice to bridge damaged vessel segment using a sufficiently long graft secured within the vessel with stent segments.
Complications arise, however, when vessel damage occurs near a vessel branch point. More elaborate, multi-component devices are required to both shield the damaged vessel portion while maintaining blood flow through the main and branch vessels. Such devices are described in the following patents and references cited therein. Each of the following patents is hereby incorporated by reference as if fully set forth herein: U.S. Pat. No. 5,906,641; U.S. Pat. No. 6,093,203; U.S. Pat. No. 5,855,598; U.S. Pat. No. 5,972,023; U.S. Pat. No. 6,129,756; U.S. Pat. No. 5,824,040; U.S. Pat. No. 5,628,787; and U.S. Pat. No. 5,957,974.
Many of the prior-art devices are suitable for vessel branches where the branch vessel leaves the main vessel at a relatively small angle (less than about 45xc2x0, or example). For larger branching angles (as large as about 90xc2x0 or even up to about 180xc2x0, for example) many prior art devices are not suitable. Such large branching angles occur at several potentially important repair sites (particularly along the abdominal aorta, at the renal arteries, celiac artery, superior and inferior mesenteric arteries, for example). Another drawback common to many devices of the prior-art is the need for transluminal access through the branch vessel from a point distal of the repair site. In many instances such access is either impossible (celiac artery, mesenteric arteries, renal arteries) or extremely difficult and/or dangerous (carotid arteries). Still other previous devices do not provide a substantially fluid-tight seal with the branch vessel, thereby partially defeating the purpose of the stent graft (i.e., shielding the repaired portion of the main vessel and/or branch vessel from intravascular fluid pressure).
It is therefore desirable to provide a bifurcated side-access intravascular stent graft and methods for fabricating and deploying the same, wherein the stent graft may be deployed transluminally to repair vessels having large-angle branch vessels (ranging from about 0xc2x0 up to about 180xc2x0, for example). It is therefore desirable to provide a bifurcated side-access intravascular stent graft and methods for fabricating and deploying the same, providing a substantially fluid-tight seal with the main vessel and the branch vessel. It is therefore desirable to provide a bifurcated side-access intravascular stent graft and methods for fabricating and deploying the same, wherein the stent graft may be deployed transluminally without distal access through the branch vessel. It is therefore desirable to provide a bifurcated side-access intravascular stent graft and methods for fabricating and deploying the same, wherein the stent graft may be readily and accurately positioned relative to the branch vessel.
Certain aspects of the present invention may overcome one or more aforementioned drawbacks of the previous art and/or advance the state-of-the-art of bifurcated intravascular stent graft and methods for fabricating and deploying the same, and in addition may meet one or more of the following objects:
To provide a bifurcated intravascular stent graft and methods for fabricating and deploying the same, wherein the stent graft may be deployed transluminally to repair vessels having large-angle branch vessels (ranging from about 0xc2x0 up to about 180xc2x0);
To provide a bifurcated intravascular stent graft and methods for fabricating and deploying the same, providing a substantially fluid-tight seal with the main vessel and the branch vessel;
To provide a bifurcated intravascular stent graft and methods for fabricating and deploying the same, wherein the stent graft may be deployed transluminally without distal access within the branch vessel;
To provide a bifurcated intravascular stent graft and methods for fabricating and deploying the same, wherein the stent graft may be readily and accurately positioned relative to the branch vessel;
To provide a bifurcated intravascular stent graft and methods for fabricating and deploying the same, wherein a primary stent graft is provided with an internal primary graft channel;
To provide a bifurcated intravascular stent graft and methods for fabricating and deploying the same, wherein a primary stent graft is provided with a side opening;
To provide a bifurcated intravascular stent graft and methods for fabricating and deploying the same, wherein the internal primary graft channel communicates with the side opening;
To provide a bifurcated intravascular stent graft and methods for fabricating and deploying the same, wherein the primary stent graft may be provided near each end thereof with a stent segment;
To provide a bifurcated intravascular stent graft and methods for fabricating and deploying the same, wherein a primary stent graft may be deployed within a main vessel with the side opening substantially aligned with a branch vessel;
To provide a bifurcated intravascular stent graft and methods for fabricating and deploying the same, wherein a secondary stent graft may be deployed within the internal graft channel and within the branch vessel; and
To provide a bifurcated intravascular stent graft and methods for fabricating and deploying the same, wherein the secondary stent graft may be provided near each end thereof with a segment.
One or more of the foregoing objects may be achieved in the present invention by a bifurcated side-access intravascular stent graft, comprising: a) first and second primary stent as segments; b) a primary graft sleeve operatively coupled near the open ends thereof to the stent segments, forming a main fluid flow channel, and having a side opening therethrough; and c) an internal graft channel formed within the primary graft sleeve. The internal graft channel has an inner open end within the primary graft sleeve and an outer open end communicating with the side opening of the primary graft sleeve, thereby forming a branch fluid flow channel between the main fluid flow channel and the side opening of the primary graft sleeve. The primary stent segments and corresponding open ends of the primary graft sleeve are adapted for engaging an endoluminal surface of a main vessel and forming substantially fluid-tight seals therewith. The primary stent graft may be delivered transluminally to a repair site of the main vessel, rotated to substantially align the side opening of the primary graft sleeve with a branch vessel, and the stent segments engaged with the endoluminal surface of the main vessel, thereby forming substantially fluid-tight seals therewith.
The bifurcated intravascular stent graft may further comprise a secondary stent graft comprising first and second secondary stent segments and a secondary graft sleeve operatively coupled to the secondary stent segments near its open ends. The secondary stent graft is adapted for passing within the internal graft channel, through the side opening of the primary graft sleeve, and into a branch vessel. The secondary stent graft may be delivered transluminally and inserted into the internal graft channel, through the side opening of the primary graft sleeve, and into the branch vessel, while remaining at least partially within the internal graft channel. The secondary stent segments may then be engaged with the inner surface of the internal graft channel and the endolumninal surface of the branch vessel, thereby forming substantially fluid-tight seals therewith.